it is a pity the plugin does not get maintained to be compatible with newer versions.
I am running 3.8 and just installed the plugin for evaluation.
Found out that the notifications use custom session fields that are not available after installation. Helped myself to add the custom fields (location, venue, room) through the facetoface settings page. Funny the help texts are available on the sessions page once you add the custom fields.
Does it make sense I report any issue that I realize to support maintenance of the activity?